1. Field of the Invention
The present invention relates to a reference solution container for a fluid analysis device. More particularly, the present invention relates to a container for a reference or calibration solution for use in a system for analyzing and measuring the gas and/or electrolyte levels in a fluid, such as blood.
2. Description of Related Art
Various fluid analysis devices are used in testing and measuring gas and/or electrolyte levels in fluids. These devices are used, for example, in medical and environmental applications to measure the gas and/or electrolyte levels in blood, urine, water, and other fluids.
Fluid analysis devices must be calibrated frequently when they are being used to test fluid samples. For example, it is preferable to recalibrate a blood analyzer after each blood sample is tested for gas and/or electrolyte levels. As a result, it is essential to provide some means of applying a reference or calibration solution to the fluid analysis devices. In many cases, a reference or calibration solution container can be coupled to the fluid analysis machine, thereby providing a ready means of recalibrating the fluid analysis machine when testing samples.
A reference or calibration container holds a reference or calibration solution that contains gases, such as oxygen and carbon dioxide, in solution at known partial pressures. Because these partial pressures are known to a relatively precise degree, the reference or calibration solution can be used to accurately calibrate the fluid analysis machine after fluid samples have been tested. Yet, such containers are frequently stored for weeks or months and are also frequently left attached to the fluid analysis machine for several weeks before they are completely depleted of reference or calibration solution and are replaced with a new container. Thus, a reference or calibration solution container must be designed such that it can reliably maintain the partial pressures of the gases in solution while the container is stored and/or attached to a fluid analysis machine.
It is also advantageous for reference or calibration solution containers to have a fluid port that is repeatedly accessible by an external fluid carrying device, such as a fluid analysis device. Multiple-access allows the reference or calibration solution container to be used for multiple tests on fluid samples and makes the container more economical and easier to use than single use containers, which must be discarded after a single recalibration. It is also desirable to provide a self-sealing mechanism on the container's repeated access port. A self-sealing, multi-access port makes the container more economical; is relatively fool-proof, in that it prevents unwanted fluid loss from the container; improves the manufacturability of the container, especially in the process for filling the container; provides more rapid access to the solution; makes the container more flexible, in that ingredients can be added to the container after it has been filled with solution; and allows any head space left in the container after filling to be easily evacuated.
While existing reference or calibration solution containers do claim to maintain the partial pressures of the gases in solution, they do not provide this capability together with a multiple-access, self-sealing port.
Accordingly, a need exists for a reference or calibration solution container that maintains partial pressures of gases in solution and that can be repeatedly accessed through a self-sealing fluid port by an external fluid carrying device. The present invention provides such a container.